Armrest

ABSTRACT

A vehicular arm has a fixed axle, an arm-rest body pivotable on the axle about its axis between a raised position and a lowered position, an abutment axially fixed on the axle and rotationally coupled to the arm-rest body, and a pusher rotationally fixed and axially shiftable on the axle. The abutment lies between the pusher and the arm-rest body. Coupling projections on the pusher and on the abutment extend toward each other and have mutually engaging faces lying in planes extending at an acute angle to the axis. A spring presses the pusher axially toward the abutment, such that, when the arm-rest body is pressed toward the lowered position with a force exceeding a predetermined limit, the faces cam the pusher axially away from the abutment and permit limited rotation of the abutment and arm-rest body on the axle.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the US national phase of PCT applicationPCT/DE2003/002784, filed 19 Aug. 2003, published 4 Mar. 2004 as WO2004/018252, and claiming the priority of German patent application10238621.8 itself filed 19 Aug. 2002 and German patent application10338414.6 itself filed 18 Aug. 2003.

FIELD OF THE INVENTION

The invention relates to an arm rest, for instance a center arm resthaving an arm-rest body pivotable about a horizontal axle between araised and a lowered position and provided with an overload protectorthat in the lowered position of the arm-rest body frees the arm-restbody to pivot downward when overloaded, the overload protector having anabutment rotatably mounted on the axle and having one side rotationallycoupled to the arm-rest body and an opposite side braced against aspring force via a spring element against a pusher rotationally fixedbut axially slidable on the axle. Such an arm rest for a motor vehicleis described in German 295 12 686.

BACKGROUND OF THE INVENTION

An arm rest of this type should be able to support a load of about 80daN. It is, however, desirable to provide a margin for safety and toprovide the arm rest with an overload protector that responds at about30 daN, that thus for example uncouples a toothed latching structure sothat when this load limit is exceeded the arm-rest body can drop down toan abutment on the motor-vehicle body. Such an overload protector isknown in general and is described in detail in above-cited German 295 12686.

The overload protector according to German 295 12 686 has however thedisadvantage that its parts are separated by quite some distance fromthe arm-rest support body and thus take up a considerable amount ofspace.

The arm rest according to EP 1,164,051 has primary and secondary partswith surfaces centered on a common axis (center axis), confronting eachother, and formed like a jaw clutch with face teeth, the primary partmounted on the arm-rest body being pivotal and also axially movable. Thelatch teeth of EP 1,164,151 having blocking and sliding flanks likeHirth teeth or a jaw clutch make it possible with fairly small primaryand secondary parts to withstand substantial angular load moments. Inaddition this known arm rest makes it possible for a control device todetermine at what angular positions the primary and secondary parts meshso that downward pivoting of the arm-rest body is blocked in theselected positions.

In EP 1,165,051 a compression spring coaxial with the secondary part andprimary part presses the primary part fixed on the arm-rest body axiallyagainst the secondary part. The axial shiftability of the primary partis limited by a plate-shaped abutment fixed on the common central axle.

In order to prevent damage to such an arm rest according to EP 1,165,051it is even preferable to set up the arm rest with an overload protectorthat responds at about 30 daN, that for example decouples the toothedlatching structure so that when the load limit is exceeded the arm-restbody can be deflected downward to a position determined by avehicle-body abutment. Such an overload protector is generally describedfor example in German 295 12 686.

OBJECT OF THE INVENTION

It is an object of the invention to, starting with the above-describedarm rest according to German 295 12 686, so to improve on the known armrest that it can withstand a greater load, takes up less space, and hasa longer service life.

This object is achieved in that the abutment and the pusher are eachformed with two axially extending and interengaging couplingprojections, the coupling-claw projections of the abutment and of thepusher having axially and radially extending flanks that bear on eachother on upward pivoting of the arm-rest body and slide flanks thatextend at an angle to the axle and that bear on each other on downwardpivoting.

According to the invention a pusher is rotationally fixed but axiallyshiftable on the axle on a side of the abutment turned away from thesecondary part and is biased by a spring force against the abutment, theabutment and the pusher each having two axially extending andinterengaging coupling-claw projections. These coupling-claw projectionsof the abutment and of the pusher have axially and radially extendingflanks that bear on each other on upward pivoting and slide flanks thatextend at an angle to the axle and that bear on each other on downwardpivoting.

In this case a force of about for example 30 daN is exerted downward onthe arm-rest body and is converted into a torque effective through theprimary and secondary parts to the fixed abutment on the axle, theangled slide flanks of the coupling-claw projections of the abutmentpressing angularly against the angled slide flanks of the coupling-clawprojections of the pusher. The result is that the pusher, which isaxially shiftable but rotationally fixed on the axle, can move againstthe force of for example a spring-washer pack away from the abutment.

This works such that the coupling-claw projections of the abutment canmove with their angled slide flanks over the coupling-claw projectionsand shift the pusher axially while the secondary part can in this mannermove out of the way.

According to the invention the abutment is rotationally coupled with thearm-rest body. The abutment thus forms in a certain way a connectorbetween the arm-rest body and the overload protector. The abutment canthus preferably be made as an integral part of the mechanism of an armrest.

This is done according to a particular embodiment of the invention inthat the abutment connecting the arm-rest body is a critical part of thesetting mechanism while the abutment is rotationally coupled via thetoothed structure with the arm-rest body when it is pivoted downward.

In this regard a toothed latching structure that only locks on downwardpivoting is particularly advantageous and has a primary part rotatableabout the axle, rotationally coupled to the arm-rest body, and coactingwith a secondary part limitedly rotatable about the axis, the toothedlatch structure having a control device that in the raised position andat the start of a downward pivoting of the arm-rest body decouples theprimary part and the secondary part from each other and that in thelowered position couples them back together, the primary part and thesecondary part having face teeth directed parallel to the axle towardeach other like a jaw clutch, the primary and/or the secondary partbeing axially movable, the control device coupling and decoupling theprimary part and secondary part being formed with at least one cam bumpengageable with the primary part or at least one cam track on theprimary part and, corresponding thereto, at least one stationary camtrack on the secondary part or at least one stationary cam bump on thesecondary part.

Thus it is important that both the primary part and the secondary parthave coaxially and confronting face teeth like a jaw clutch and that theprimary part and/or the secondary part are axially shiftable.

The jaw clutch made according to the invention with Hirth teeth, that isteeth with slide flanks and blocking flanks, allows even very smallprimary and secondary parts to withstand considerable loads or torques.In addition this construction allows one to establish, with theassistance of a control device, the exact angular region where theprimary and secondary part come into mesh with each other in order to,in this region, block downward pivoting of the arm-rest body.

The control device according to the invention has a cam bump riding onthe primary part, at least one cam track turning with the primary part,or as an alternative at least one cam track turning with the secondarypart and at least one cam bump riding on the secondary part.

According to a particularly preferable feature of the invention, thereis a control ring between the primary part and secondary part,rotationally coupled to the primary part, and having a side turnedtoward the secondary part forming the cam bump or the cam track. Thecontrol ring forming a specific part according to the invention canprovide a particularly advantageous level of control that can beobtained with a part built into the primary part.

The transmission of substantial rotary forces or torques by the faceteeth of the primary and secondary part according to the invention isoptimized according to the invention in that the primary part and thesecondary part each have a circular ring forming the face teeth and thatcan be large enough that the outer periphery of the circular ring is thesame as the outer periphery of the primary and/or secondary part so thatthe face teeth cover quite an area and can extend over the entireperiphery of the primary and secondary parts.

In order to block downward pivoting of the arm-rest arm all the teeth,that is a multiplicity of teeth, lock together while in the knownsystems (German 199 15 469) only one tooth, namely the tip of thelatching pawl, engages in a stationary seat.

In addition the dependence of the control ring on the pivotal movementof the arm-rest body for a limited angle is eliminated in that theprimary part has a cam bump projecting toward the secondary part andengaging in a cam recess formed in a face directed toward the primarypart of the control ring which has on its side turned toward thesecondary part at least one and in particular two cam bumps thatcooperate with the cam track fixed to the secondary element, wherebymore particularly the cam recess of the control ring has a greaterangular dimension than the cam bump of the primary part.

As a result the primary part, both in the lowered position and at thestart of upward pivoting as well as in the raised position and at thestart of downward pivoting of the arm-rest body, has some lost motionbefore the cam bump engages with the first or second abutment face ofthe cam recess.

According to a further embodiment of the invention the axle is splinedalong its entire length, the primary part, the control ring, thesecondary part, and the abutment each having a smooth central borethrough which the axle extends and which allows free rotation, thepusher at least having a central bore complementary to and rotationallycoupling it to the axle.

In order to avoid the central axle being a relatively expensive part,according to the invention a shaft is used having full-length splines.Such a splined shaft are standard items sold by length. Such a splinedshaft has the advantage that the primary part, the control ring, thesecondary part, and the abutment can each be mounted rotatably by asmooth central throughgoing bore on the splined shaft. In case on thecontrary something needs to be angularly coupled to the axle, as forexample a pusher described more fully below, this part can be providedwith a central throughgoing bore complementary to the splined shaft.

The spline shaft also makes it possible for something to slide ifnecessary axially along the axle, both the elements carried thereon withsmooth throughgoing bores and a part with a complementarily shaped bore,e.g. the pusher. In case one of these elements, be it one with a smoothcentral throughgoing bore or one with a splined central bore, needs tobe axially fixed on the shaft, according the invention the axle isprovided with at least one recess on its outer surface, as e.g. anannular groove for holding an annular retaining element, e.g. a snapring.

BRIEF DESCRIPTION OF THE DRAWING

The drawing shows preferred embodiments, that is a first embodiment(FIGS. 1–10C) and a second embodiment (FIGS. 11–17A), therein:

FIG. 1 is a three-dimensional representation of the mechanical elementsof an arm rest;

FIG. 2 shows the elements of FIG. 1 without the outer tube shielding theinner parts;

FIGS. 3 and 4 are exploded views of the structure of FIG. 2 with aschematically illustrated arm support seen from two different angles;

FIG. 5 is a view like FIG. 3 but seen at an 180° opposite angle;

FIG. 6 is a side view of the primary part of FIGS. 2 and 3;

FIG. 6A is an end view taken in the direction of arrow VIA of FIG. 6;

FIG. 6B is a sectional view taken along plane VIB—VIB of FIG. 6A;

FIG. 7 is an end view of a control ring;

FIG. 7A is a radial cross section taken along line VIIA—VIIA of FIG. 7,with FIG. 7A corresponding to the FIG. 3 embodiment;

FIG. 7B is a side view of control ring in a position offset to that ofFIG. 7A by 180°;

FIG. 7C is an end view taken in the direction of arrow VIIC of FIG. 7B;

FIG. 8 is a side view of a secondary part of the embodiment of FIG. 3;

FIG. 8A is an end view taken in the direction of arrow VIIIA of FIG. 8;

FIG. 8B is an axial section taken along line VIIIB—VIIIB of FIG. 8A;

FIG. 8C is a section offset by 90° from that of FIG. 8 b and taken alongline VIIIC—VIIIC of FIG. 8A;

FIG. 8D is an end view taken in the direction of arrow VIIID of FIG. 8;

FIG. 9 is a side view of an abutment part according to the embodiment ofFIG. 3;

FIG. 9A is an end view taken in the direction of arrow IXA of FIG. 9;

FIG. 9B is an end view taken in the direction of arrow IXB of FIG. 9;

FIG. 9C is an axial section taken along line IXC—IXC of FIG. 9B;

FIG. 9D is an axial section offset by 90° from that of FIG. 9C and takenalong line IXD—IXD of FIG. 9B;

FIG. 10 is an end view of a pusher part, taken in the direction of arrowX of FIG. 10B;

FIG. 10A is an axial section taken along line XA—XA of FIG. 10;

FIG. 10B is a side view taken in the direction of arrow XB of FIG. 10;

FIG. 10C is an end view taken in the direction of arrow XC of FIG. 10B;

FIG. 11 is a perspective view of the elements of an alternate arm rest;

FIG. 12 is a view like. FIG. 11 of the elements but with out the outertube shielding the inner parts;

FIG. 13 is an exploded view with a schematically illustrated arm-restsupport;

FIG. 14 is a side view of the primary part of the embodiment of FIGS. 12and 13;

FIG. 14A is an end view of the primary part taken in the direction ofarrow XIVA of FIG. 14;

FIG. 14B is an axial section taken along line XIVB—XIVB of FIG. 14A;

FIG. 15 is an end view of the control ring;

FIG. 15A is an axial section taken along line XVA—XVA of FIG. 15, FIG.15A corresponding to the embodiment of FIGS. 12 and 13;

FIG. 15B is a side view of the control ring in a position offset by 180°to that of FIG. 15A;

FIG. 15C is an end view taken in the direction of arrow XVC of FIG. 15B;

FIG. 16 is a side view of the secondary part of the embodiment of FIGS.12 and 13;

FIG. 16A is an end view taken in the direction of arrow XVIA of FIG. 16;

FIG. 16B is an axial section taken along line XVIB—XVIB of FIG. 16A;

FIG. 16C is an axial section in a position offset by 90° to that of FIG.16B and taken along section line XVIC—XVIC of FIG. 16A;

FIG. 16D is an end view taken in the direction of arrow XVID of FIG. 16;

FIG. 17 is an end view taken in the direction of arrow XVII of FIG. 17A;and

FIG. 17A is an axial section taken along line XVIIA—XVIIA of FIG. 17.

SPECIFIC DESCRIPTION

In the following drawing, in spite of structural differences, the samereference numerals are applied to analogous elements in both theembodiment of FIGS. 1–10C and the embodiment of FIGS. 11–17A.

The arm rest is shown in general (see FIGS. 3 and 13) at 10. The supportelement of the mechanism 11 of the arm rest 10 is a stationary axle 12fixed by mounts 13 to an unillustrated vehicle body. The axle 12 has inthe embodiment of FIGS. 11–17A a corrugated profile, that is externalsplines. Much of the mechanism 11 is surrounded by an outer shield tube14 having at each end a shoulder 15 bearing on a straight inner endportion 16 of a respective arcuate arm-rest support arm 17 or 18. Inthis manner the support arm 17 shown in FIGS. 1–4 and FIGS. 11 and 13 onthe right and in FIG. 5 on the left is rotationally fixed to the supportarm 18 shown on the left in FIGS. 1–4 and FIGS. 11 and 13 and in FIG. 5on the right.

Two generally U-shaped hollow arms 19 (FIG. 2) extend from an arm-restsupport 20 and are connected in an unillustrated manner with the twosupport arms 17 and 18. Since forces F against the arm-rest support 20are mainly transmitted by the arm 17 into the mechanism 11, the arm 17in the following is referred to generally as the “arm-rest body” or“pivotal arm-rest body.”

As shown in particular in FIG. 3, a hexagonal socket 21 of the supportarm 17 fits over a hexagonal nut 22 formed integrally with a primarypart P. As shown in FIGS. 11 and 13, instead of a hexagonal socket thereis a Torx socket 21 and instead of the hexagonal nut there is a Torxformation 22 on the primary part P. Each end of the axle 12 carries anonrotatable end part 58 (FIG. 13). The support arm 18 is rotationallysupported by a sleeve 59 on the axle 12.

The primary part P as well as a control ring R, a secondary part S, anabutment W, a pusher D, a spring-washer pack T, and a setting nut E aremounted coaxially on the axle 12. The setting nut E or an equivalentpart is not shown in FIGS. 11–13. In order to axially fix the supportarm 17, a snap ring 23 engages in an annular groove 24 of the axle 12.

The primary part is shown in more detail in FIGS. 6–6B and 14–14B. Theprimary part P illustrated in FIGS. 6 and 14 corresponds to theembodiment of FIG. 3 and FIGS. 12 and 13, 10 respectively. The primarypart P has face teeth Z1 shaped like the Hirth teeth of a jaw clutch, sothat the teeth each have a shallow slide flank facing in one directionand a steep or undercut blocking flank facing in the opposite direction.The teeth Z1 are arrayed in a continuous ring whose outer periphery isvirtually level with the outer periphery of the primary part P so thatthe teeth Z1 have as a result of this formation considerableload-bearing capacity and thus are able to withstand relatively largeangular loads.

The secondary part S has face teeth Z2 just like the teeth Z1 of theprimary part P. FIGS. 8 and 16 show the secondary part in the embodimentof FIG. 3 and of FIGS. 12 and 13, respectively. The face teeth Z2 of thesecondary part S are oriented relative to the face teeth Z1 of theprimary part P such that when the support arm 17 swings upward as shownby arrow A (see FIGS. 3 and 13) the blocking flanks of the face teeth Z1of the primary part P slide over the slide flanks of the face teeth Z2of the secondary part S which normally is nonrotatable on the axle 12.

In case however the blocking flanks of the face teeth Z1 and Z2 bearangularly on each other and the force F (see FIGS. 3 and 13) is exerteddownward on the arm support 20, downward-swing torque in the directionof arrow N is exerted on the face teeth Z1 of the primary part P. Theresult is that the blocking flanks of the nonrotatable secondary part Slock and downward pivoting is impossible in the rotation direction N.

As mentioned, the secondary part S normally cannot rotate on the axle12, but is rotatably mounted with its smooth central hole 26 on the axle12 like the primary part P with its smooth central bore 25. In case ofan overload, the situation is different for the secondary part S as willbe described in the following.

In the embodiment of FIGS. 3 and 13 the end face turned away from theprimary part P of the secondary part S is juxtaposed with the abutment Wthat fits with a smooth central bore 27 over the axle 12 and is axiallysecured by a snap ring 28 (axial retaining ring) fitting in anotherradially outwardly open groove 24 on the axle 12. The secondary part Sand the abutment W are formed on their confronting end faces withrespective axially projecting coupling claws 29 and 30 that serve torotationally couple the axially shiftable secondary part S and theabutment W axially fixed on the axle 12. Each coupling claw 29 and 30and each recess 31 formed between adjacent coupling claws 29 of thesecondary part S and claws 30 of the abutment W is formed with anaxially open blind hole 33 in which can fit a respective one of fourcoil compression springs 34 extending parallel to the axle 12.

Instead of the four compression springs 34 a single coaxial compressionspring (see 34 in FIG. 13) can be provided between the secondary part Sand the abutment W, bearing on unillustrated annular shoulders of therespective outer surfaces of the secondary apart S and the abutment W.

The end face of the abutment W turned away from the secondary part S isjuxtaposed with the pusher D. The pusher D (see FIGS. 10–10C) has aninternal polygonal bore 35 that can slide but not rotate on acomplementary square region 53 of the axle 12. In the embodiment ofFIGS. 11–17A the pusher D (see FIGS. 17 and 17A) has instead of thepolygonal bore a central hole 35 that is splined like the axle 12 sothat the pusher D cannot rotate but can slide on the axle 12.

The abutment W and the pusher D have respective interengageable couplingprojections 36 and 37 on their confronting end faces. The coupling-clawprojections 36 of the abutment W have axially and radially extendingfaces 38 that bear on axially and radially extending faces 39 of the twocoupling-claw projections 37 of the pusher D.

In addition the two coupling-claw projections 36 of the abutment W bearwith faces 40 angled to the axle 12 on complementarily angled faces 41of the two coupling-claw projections 37 of the pusher D.

The washer-spring pack T is provided at the end face of the pusher Dturned away from the abutment W. The spring pack biases the pusher Dwith a spring force against the abutment W which cannot move axially onthe axle 12. The setting nut E (which is the same in FIGS. 12 and 13 butnot shown) is carried on an external screwthread of the axle 12 so thatthe prestressing of the spring pack T can be set and adjusted.

The control ring R mounted between the primary part P and the secondarypart S and having a smooth central bore 54 through which passes the axle12 fulfills a particular function, is rotationally coupled with theprimary part P, and has on its end face turned toward the secondary parttwo control cam bumps 42 (see FIGS. 7–7C; FIGS. 15–15C) that coact withcam tracks 43 of the secondary part S.

The primary part P (see FIGS. 6–7B and FIGS. 14–14B) has a coupling bump44 projecting toward the secondary part S and engaging in a couplingrecess 45 open on the control ring R toward the primary part P.

The primary part P and the secondary part S have the end teeth Z1 and Z2arrayed in circular rings. The outer periphery of each ring generallycorresponds to the outer periphery of the body of the respective primarypart P or secondary part.

Each set of face teeth Z1 and Z2 extends around the entire periphery ofthe respective primary part P or secondary part S.

The primary part P and the secondary part S are formed radially inwardof the respective teeth Z1 and Z2 with generally cylindrical recesses 46and 47. The cylindrical recesses 46 and 47 are open toward each otherand thus form a cavity in which the control ring R is received. Forcertain applications it can be advantageous to provide more frictionbetween the recess 46 of the primary part P and the correspondingsurface of the control ring R than between the recess 47 of thesecondary part and the other corresponding surface of the control ringR. To this end the recess 46 of the primary part P is formed with acircular V-shaped groove 56 and the control ring R with a complementaryV-shaped ridge 60.

The coupling recess 45 of the control ring R extends over a greaterangle β than the angle α of the coupling bump 44 of the primary part P.For example the angle β=60° and the angle α=45° so that the couplingbump 44 has about 15° of play.

The two cam bumps 42 of the control ring R are engageable in respectivecam recesses 48 of the cam tracks 43 of the secondary part S. The camtracks 43 form annular surfaces centered on the axle 12 at the base ofthe cylindrical recess 47 of the control ring R.

The arm rest shown in the drawing functions as follows:

When the arm-rest support 17 is in its lowermost position, the couplingbump 44 bears on a second abutment face 50 of the coupling recess 45 ofthe control ring R. Since the angle β of the coupling recess 45 is forexample 15° larger than the angle α of the coupling bump 44, the primarypart P fixed rotationally to the arm-rest body 17 has about 15° of play.The arm-rest body can ratchet over for example four teeth of therotationally fixed face teeth Z2 of the secondary part while movingthrough this play.

Immediate downward movement out of one of these four positions is notpossible, because the teeth Z1 and Z2 are locked together.

A limited upward pivoting of 15° is nonetheless possible, because theblocking flanks of the teeth Z1 of the primary part P can slipunhindered over the slide flanks over the nonrotatable teeth Z2 of thesecondary part S.

In this manner it is possible to shift the arm-rest body 17 upward intoan upright position, but the ratcheting sound made by the teeth Z1 andZ2 is somewhat bothersome. In order to eliminate this noise, theinvention works as follows:

As soon as the coupling bump 44 comes into contact against a firstabutment face 49 of the coupling recess 45 of the control ring R and theupward movement continues in rotation direction A, the two cam bumps 42engage with angled faces 51 on angled faces 52 of the secondary-part camrecesses 48 and rise therefrom as indicated at A in FIGS. 7, 7C, and 8Dand in FIGS. 15, 15C, and 16D.

In this manner the secondary part S is shifted back away from theprimary part P against the force of the springs 34 so that the teeth Z1and Z2 disengage from each other and the support arm 17 can be swungsilently into its upright position. During this upward movement the twocam bumps 42 slide on the flat cam tracks 43.

If now, starting from the upright position of the arm-rest body 17, adownward pivoting is initiated, the coupling bump 44 moves in theangular direction N from the first abutment face 49 back into theabove-described starting position against the abutment face 50.

Thus the cam bumps 42 move again over the flat cam tracks 43 backward inangular direction N (see FIGS. 7C and 8D as well as FIGS. 15C and 16D)and finally slide back again into the cam recesses 48 of thesecondary-part cam tracks 43, whereupon the arm-rest body 17 findsitself again in its above-described lowermost starting position and theface teeth Z1 and Z2 are again in mesh with each other.

In order to insure that in every case when downwardly pivoting in theangular direction N the coupling bump 44 moves from the first abutmentface back into the above-described position on the abutment face 15 sothat a subsequent adjustment upward in direction A ensures a shift of15°, the invention provides the following as shown in the embodiment ofFIGS. 11–17A:

Control bumps 55 project from the flat cam tracks 43 in an axialdirection x toward the control ring R immediately adjacent in the upwardrotation direction A from each secondary-part cam recess 48.

As soon as the coupling bump 44 engages against the first abutment face49 of the cam recess 45 of the control ring R and upward pivotingcontinues in angular direction A, the two cam bumps 42 slide with theirangled flanks 51 over the angled flanks 52 of the secondary-part camrecesses 48 and rise out of them and then, as shown in FIG. 16D, comeinto engagement with the control bumps 55 and slide over them. Thispushes the secondary part S against the spring force, that is againstthe force of the single coil spring 34, away from the primary part P sothat the face teeth Z1 and Z2 disengage from each other and the supportarm 17 can move silently into its upright position. During this upwardpivoting in the direction A the two cam bumps 42 slide over the flat camtracks 43. When however, starting in the completely raised position ofthe support arm 17, which is defined by an external abutment, downwardpivoting in the direction N is initiated, the coupling bump 44 moves inthe direction N from the first abutment face 49 back into itsabove-described starting position against the abutment face 50. In orderthat this reverse rotation can take place, there must be some relativemovement between the primary part P and the control ring R, which ismade possible by friction in the embodiment of FIGS. 1–10C so as to holdback the control ring R relative to the secondary-part cam tracks 43.This holding back is done however according to FIG. 16D by the controlbump 55 because the cam bump 42, when moving downward in the directionN, moves against a face 57 of the control bump 55 and thus ensuresengagement of the primary-part coupling bump 44 against the secondabutment face 50 of the control ring R.

For the situation when the arm-rest body 17 is in its lowermost positionand an overload is applied in direction F to the arm-rest body 17 so asto press the arm-rest body 17 downward in pivot direction N, the teethZ1 and Z2 are locked together.

The rotary coupling by means of the coupling claws 29 and 30 of thesecondary part S and the abutment W transmits overload torque to theabutment so that the abutment W rotates in direction N (see FIGS. 2 and12) and the angled slide faces 40 of the coupling-claw projections 36 ofthe abutment W act on the angled slide faces 41 of the coupling-clawprojections 37 of the pusher D in axial direction x. In this manner incase of an overload in rotation direction N, the abutment W can rotaterelative to the pusher D and deflect so as to unload the arm rest 10.

1. A vehicular arm rest comprising: a fixed axle extending along an axisand having a nonround portion; an arm-rest body pivotable on the axleabout the axis between a raised position and a lowered position; anabutment axially fixed on the axle and rotationally coupled to thearm-rest body; a pusher rotationally fixed and axially shiftable on theaxle and having a nonround bore fitting complementarily over thenonround portion of the axle, the abutment lying between the pusher andthe arm-rest body; coupling projections on the pusher and on theabutment extending toward each other and having mutually engaging faceslying in planes extending at an acute angle to the axis; and a springpressing the pusher axially toward the abutment, the mutually engagingfaces being angled and the spring having a force such that, when thearm-rest body is pressed toward the lowered position with a forceexceeding a predetermined limit, the mutually engaging faces cam thepusher axially away from the abutment and permit limited rotation of theabutment and arm-rest body on the axle.
 2. The vehicular arm restdefined in claim 1 wherein the nonround portion is of generally squaresection.
 3. The vehicular arm rest defined in claim 1 wherein the springis a pack of spring washers.
 4. A vehicular arm rest comprising: a fixedaxle extending alone an axis; an arm-rest body pivotable on the axleabout the axis between a raised position and a lowered position; anabutment axially fixed on the axle and rotationally coupled to thearm-rest body; a pusher rotationally fixed and axially shiftable on theaxle, the abutment lying between the pusher and the arm-rest body;coupling projections on the pusher and on the abutment extending towardeach other and having mutually engaging faces lying in planes extendingat an acute angle to the axis; a pack of spring washers pressing thepusher axially toward the abutment, the mutually engaging faces beingangled and the spring pack having a force such that, when the arm-restbody is pressed toward the lowered position with a force exceeding apredetermined limit, the mutually engaging faces cam the pusher axiallyaway from the abutment and permit limited rotation of the abutment andarm-rest body on the axle; and a setting nut threaded on the shaft androtatable on the shaft to move toward and away from the pusher, thespring pack being braced between the setting nut and the pusher.
 5. Thevehicular arm rest defined in claim 4 wherein the axle has a nonroundportion and the pusher has a complementarily nonround bore fitted overthe nonround portion.
 6. A vehicular arm rest comprising: a fixed axleextending along an axis; an arm-rest body pivotable on the axle aboutthe axis between a raised position and a lowered position; an abutmentaxially fixed on the axle and rotationally coupled to the arm-rest body;a pusher rotationally fixed and axially shiftable on the axle, theabutment lying between the pusher and the arm-rest body; couplingprojections on the pusher and on the abutment extending toward eachother and having mutually engaging faces lying in planes extending at anacute angle to the axis; a spring pressing the pusher axially toward theabutment, the mutually engaging faces being angled and the spring havinga force such that, when the arm-rest body is pressed toward the loweredposition with a force exceeding a predetermined limit, the mutuallyengaging faces cam the pusher axially away from the abutment and permitlimited rotation of the abutment and arm-rest body on the axle; aprimary part rotatably about the axis on the axle, axially fixed on theaxle, fixed rotationally to the arm-rest body, and formed with an arrayof axially directed teeth; a secondary part at most limitedly pivotalabout the axis on the axle, axially shiftable on the axle, and having anarray of axially directed teeth meshable with the primary-part teeth,the teeth of both parts being angled such that when meshed they inhibitmovement of the arm-rest body from the raised to the lowered positionbut permit movement of the arm-rest body from the lowered to the raisedposition; spring means braced axially between the abutment and thesecondary part for urging the secondary-part teeth into mesh with theprimary-part teeth; and control means between the primary part and thesecondary part and including cam formations for pushing the secondarypart away from the primary part on pivoting of the primary part from theraised position of the arm-rest body toward the lowered position fordecoupling the primary-part teeth from the secondary-part teeth and forcoupling the primary-part teeth with the secondary-part teeth onpivoting into the lowered position.
 7. The vehicular arm rest defined inclaim 6 wherein the control means includes: a control ring between theprimary part and the secondary part and having a cam side turned towardone of the parts and a coupling side turned toward the other of theparts, the one part having a cam side turned toward the control-ring camside and the other part having a coupling side turned toward thecontrol-ring coupling side, the cam formations being on the cam sides; acoupling bump on one of the coupling sides and projecting toward theother coupling side; and a coupling recess on the other of the couplingsides open toward the one coupling side and receiving the cam bump. 8.The vehicular arm rest defined in claim 7 wherein each of the arrays ofteeth is substantially circular and both of the parts are formedradially inward of the respective arrays with generally cylindricalrecesses open toward each other and forming a cavity holding the controlring.
 9. The vehicular arm rest defined in claim 7 wherein the couplingbump has a predetermined angular dimension and the coupling recess has apredetermined angular dimension greater than that of the coupling bump,whereby the coupling bump can move angularly within the coupling recesspermitting limited relative angular movement between the control ringand the other part.
 10. The vehicular arm rest defined in claim 6wherein the cam formations include: an annular cam track on one of thecam faces; a cam recess in the track on the one face and open toward theother cam face; a cam bump formed on the other cam face, projectingaxially toward the other of the cam faces, and riding on the cam track,the cam bump, cam track, and cam recess being constructed such that whenthe cam bump is riding on the cam track the primary-part teeth are heldout of mesh with the secondary-part teeth and when the cam bump isengaged in the cam recess the primary-part teeth mesh with thesecondary-part teeth.
 11. The vehicular arm rest defined in claim 10wherein the track is generally circular, planar and perpendicular to theaxis.
 12. The vehicular arm rest defined in claim 6 wherein the controlmeans shifts the cam bump out of the cam recess on pivoting toward theraised position, also shifts the cam bump out of the cam recess onpivoting out of the raised position toward the lowered position, butpositions the cam bump in the recess on pivoting toward the loweredposition from any position between the raised and lowered positions. 13.The vehicular arm rest defined in claim 6, further comprising formationsrotationally coupling the abutment to the secondary part.
 14. Thevehicular arm rest defined in claim 13 wherein the formations couplingthe abutment to the secondary part include a plurality of axiallyextending coupling teeth on the abutment and on the secondary parthaving faces extending parallel to the axis and bearing angularly oneach other.
 15. The vehicular arm rest defined in claim 14 wherein theabutment and secondary part are formed between the teeth with recesses,the coupling teeth of the abutment fitting in the recesses of thesecondary part and the coupling teeth of the secondary part fitting inthe recesses of the abutment, the teeth and recesses being formed withaxially aligned blind bores, the spring means including respectivecompression springs in the axially aligned blind bores.
 16. Thevehicular arm rest defined in claim 6, further comprising a shield tubesurrounding the pusher, the abutment, the secondary part, the primarypart, and the spring.
 17. The vehicular arm rest defined in claim 16wherein the arm-rest body includes a pair of arms extending radiallyfrom the axle, one of the arms being fixed to the primary part, theshield tube having formations coupling both of the arms rotationallytogether.
 18. The vehicular arm rest defined in claim 6 wherein the axleis splined along its entire length, the pusher being splined to theaxle, the abutment, secondary part, and primary part having smooth boresthrough which the axle passes.